Re: [Discuss-gnuradio] FX2 firmware

[Stefan Bruens]

On Wednesday 06 May 2009 18:35:36 Dominik Auras wrote:
> Do you have, maybe, an idea why TX bandwidth is limited? Interestingly
> enough, 32.7 Mb/s is the limit on my computer and my notebook. Of
> course, I made the tx loop on the host as short as possible, set
> SCHED_FIFO and rtprio to 49, and played with fusb_nblock/size etc.

Are you transmitting random data, or a stream of zeros? In the latter case 
(IIRC), every 6 zeros will have a single 1 added to aid clock recovery, 
limiting net bandwidth to 6/7 (which is about 42MByte). Try transmitting 
random data, a stream of ones should be fine to.

For detail have a look at the USB spec.

Stefan

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